In this paper, a continuum model is proposed so that a Stone-Wales (SW) defected carbon nanotube (CNT) is replaced by an initial circumferential crack in a continuum cylindrical shell. For this purpose, the critical energy release rate and then the fracture toughness of a defected CNT are calculated using the results of an existing atomistic-based continuum finite element simulation. Finally, t...

Circumferential crack detection of small diameter tubes is a difficult problem to solve in eddy current testing. The three-dimensional simulation model established through electromagnetic field software analyze the distribution traditional bobbin probe and transverse cylindrical tubes. results show that circumferential has more marked disturbance generated by latter. Based on research, new type...

Finite element method (FEM) is one of the most famous methods which has many applications in varies studies such as the study of crack propagation in engineering structures. However, unless extremely fine meshes are employed, problem arises in accurately modelling the singular stress field in the singular element area around the crack tip. In the present study, the crack growth simulation has b...

The present work deals with the effect of an external circumferential elliptical crack located at thickness transition on a varied stepped diameter pipe . The purpose is the application of the extended finite element method (XFEM) for the calculation of SIF at the thickness transition region of pipe considering internal pressure and compare the effect of the crack between pipes straight and wi...

Results of a geometrically nonlinear finite element parametric study to determine curvature correction factors or “bulging factors” that account for increased crack-tip stresses due to curvature for longitudinal and circumferential cracks in unstiffened cylindrical shells subjected to combined loads are presented. Nondimensional parameters varied in the study include the shell curvature paramet...

In an earlier paper it was suggested that a knowledge of the elastic-stress variation in the neighborhood of an angular corner of an infinite plate would perhaps be of value in analyzing the stress distribution at the base of a V-notch. As a part of a more general study, the specific case of a zero-angle notch, or crack, was carried out to supplement results obtained by other investigators. Thi...

Based on the analytical solution of Crouch to the problem of a constant discontinuity in displacement over a finite line segment in an infinite elastic solid, in the present paper, the crack-tip displacement discontinuity elements, which can be classified as the left and the right crack-tip elements, are presented to model the singularity of stress near a crack tip. Furthermore, the crack-tip e...

An innovative technique, called conversion, is introduced to model circumferential cracks in thin cylindrical shells. The semi-analytical finite element method applied investigate the modal deformation of cylinder. including crack divided into three sub-elements with four nodes which stiffness matrix enriched. characteristics are included relations through conversion matrices and a rotational s...

Asymptotics of solutions to the Laplace equation with Neumann or Dirichlet conditions in the vicinity of a circular singular edge in a three-dimensional domain are derived and provided in an explicit form. These asymptotic solutions are represented by a family of eigen-functions with their shadows, and the associated edge flux intensity functions (EFIFs), which are functions along the circular ...

Numerical simulation of cracked structures is an important aspect in structural safety assessment. In recent years, there has been an increasing rate of development of numerical codes for modeling fracture procedure. The subject of this investigation is implementing automated fracture models in the DYNA3D nonlinear explicit finite element code to simulate pseudo 3-D crack growth procedure. The ...